1. Technical Field
The present invention relates to a food conditioning chest for storing foodstuffs and, in particular, to a food conditioning chest in which tempered air is circulated to preserve the foodstuffs.
2. Background Art
Food chests are conventionally used in the food services industry, wherein it is desired to preserve a large quantity of stored food over a relatively long period of time. Commonly, food chests are used in institutional environments, such as in schools or hospitals, in which many servings of food are stored in a food chest and are periodically dispensed for consumption by an individual. Often servings are continuously dispensed from a food chest as in a `cafeteria line`-type usage.
Because of the large number of servings often stored within a food chest, the process of dispensing the servings can become quite protracted, and some servings may be stored in the chest for a relatively long time before they are ultimately dispensed. In order to adequately preserve the food, it is therefore important that food chests have some capability of maintaining food stored therein in a proper condition. Normally food servings must either be kept refrigerated, requiring that heat energy be drawn from the interior of the food chest, or the food servings must be continuously warmed, requiring that heat be supplied to the interior of the food chest.
One approach to conditioning food contained within a food chest has been to circulate conditioned air about the food. Air is drawn from openings in the chest and then appropriately conditioned, as by heating or cooling the air. Conditioned air is then forced back into the food chest to transfer thermal energy between the interior of the chest and the air to thereby condition the food. The efficiency with which the food is conditioned is directly related to the amount and the condition of air which is circulated within the food chest.
One proposed air circulating system is shown in U.S. Pat. No. 3,962,962 to Anderson. Anderson discloses a hot cabinet server in which pre-packaged foods are stored in a rectangular bin. The bin has opposite upright side walls having vent openings to allow air to flow into and out of the bin, with both inlet vents and outlet vents provided on the same side of the bin. A common fan draws air from the bin through the outlet vents and attempts to force air into the bin through the adjacent inlet vents, such that the proximate, opposed flows impede air circulation and limit the efficiency with which conditioned air can be supplied to the foods contained in the bin. More specifically, cool air is drawn upwardly out of the bin and tends to redirect the incoming, heated air such that heat is prevented from efficiently reaching the food at the bottom of the bin. In one form of the known air circulating system, air is drawn through only a single return side of the bin, further limiting air circulation.
In addition to the reduced volume of air which is circulated with the known device, because the pre-conditioned `return` flow and the conditioned `intake` flow are routed closely together, thermal losses further impede the efficiency of the food conditioning. On the sides of the bin having both inlet and outlet vents, pre-conditioned return air is drawn from the bin and travels in a path adjacent the conditioned intake air moving toward the inlet vents. Heat is conducted between the return and the intake flows and the efficiency of the food conditioning process is reduced.
Another problem with the Anderson structure occurs at startup. The unheated return air is drawn against the heater so as to effect cooling thereof. This lengthens the startup time for the device.